Organic electroluminescent devices, OLEDs have shown great potential in the fields of display and lighting due to their advantages of simple fabricating process, wide range of materials, controllable structures, and slimness and curling. OLED display is a very promising flat panel display technology, it has the characteristics of self-luminous, simple structure, ultra-thin, fast response, wide viewing angle, low power consumption and can achieve flexible display, known as “Dream Display”.
It is noteworthy that, although the OLED has achieved commercial production, but the device luminous efficiency is still much room for improvement. In the conventional technology, the electron injection layer (cathode modification layer) of the OLED is mostly a metal oxide or a polymer material. During the long-term research and development process, the inventor of the present application found that the above-mentioned technologies are not good enough for electron injection capability, and have high fabrication cost, with low luminous efficiency of the device.